Apparatus for removing moisture

ABSTRACT

Apparatus for removing moisture from flowable material by the actions of pressure and vacuum comprises a housing provided with an inlet suction opening and a discharge conduit, a hollow piston rotatably mounted in said housing and having a liquid-permeable shell, said piston is oval in cross-section and defines within said piston a cavity and with said housing a handling chamber having a suction end and a discharge end, a backed gate mounted in said housing, a mechanism positively maintaining said gate in sealing contact with said shell between said discharge and suction ends, a vacuum pump and a liquid pump connected to said cavity, and an adjustable throttle valve controlling the crosssection of said discharge conduit.

United I States Patent Nebel [54] APPARATUS FOR REMOVING MOISTURE Franz P. Nebel, Muhlberg 11, A 5132 Geretsberg, Austria 22 Filed: May 19, 1970 21 Appl.No.: 38,846

[72] Inventor:

U.S. Cl. ..l00/l2l, 100/156, 100/210 FieldofSearch ..100/ll0,11l,1l6,121,156, 100/177, 178, 210; 146/39, 3.12

[56] References Cited UNITED STATES PATENTS 3,000,294 9/1961 Lowe et a1. 100/12 1 [4 1 June 13, 1972 Asplund ..100/121 Frykhult ..l00/12l ABSTRACT Apparatus for removing moisture from flowable material by the actions of pressure and vacuum comprises a housing provided with an inlet suction opening and a discharge conduit, a hollow piston rotatably mounted in said housing and having a liquid-permeable shell, said piston is oval in cross-section and defines within said piston a cavity and with said housing a handling chamber having a suction end and a discharge end, a backed gate mounted in said housing, a mechanism positively maintaining said gate in sealing contact with said shell between said discharge and suction ends, a vacuum pump and a liquid pump connected to said cavity, and an adjustable throttle valve controlling the cross-section of said discharge conduit.

PATENTEnJua 13 mm V gl I.

INVENTOR:

FRANZ P NEBEL ATTORNEY I APPARATUS FOR REMOVING MOISTURE Among the apparatus for removing moisture, those best known include screw presses, mainly for squeezing fruit, or arrangements in which the material from which moisture is to be removed is squeezed between two roller-driven filter belts. In other apparatus, moisture is removed by the action of a vacuum. A drum is provided at its periphery with a plurality of vacuum cells and a screen or filter belt moves in contact with the periphery of the drum. All these apparatus can remove liquid only at a low rate and the capital requirement and operating costsof some of them are very high compared to said liquid removal rate.

The present invention provides a dual-action type apparatus for removing moisture. The material from which moisture is to be removed is squeezed continuously under an adjustable pressure by a rotary'drum type piston. Additional moisture is removed at the same time by the. action of a vacuum maintained in the hollow rotary piston, which has a shell formed as a filter screen. The residues of squeezed material adhering to the shell of the rotary piston are automatically scraped ofi. Thefine sheet metal screen forming the periphery of the rotary piston is continuously cleaned by a shear blade so that the screen cannot become clogged. This combination of a plurality of operations results in a removal of moisture at a high rate by an apparatus which is simple and can be manufactured at a low cost.

An embodiment of the invention is shown by way of example in the drawing, in which l lG. l is a sectional view showing the apparatus and taken at right angles to the'driving shaft,

FIG. 2 is a sectional view taken along the axes,

FIG. 3 is a sectional view taken through the rotary press piston and FIG. 4 is a fragmentary view showing the rotary press piston and its scraping device. i In the illustrated embodiment, the apparatus according to the invention comprises a housing body 1, a left-hand end cover 2, a right-hand end cover.3, a hollow rotary drum type piston 4, a partly hollow drivingshaft 5 driven by conventional motor means, a drainpipe 6, a backed gate 16 mounted on a pivot 7, bearing brackets 8, means 17 for positively controlling the gate, a hinged valve for controlling the pressure applied, a lever 11 and spring 12 associated with the valve 10, and a mounting bracket 9 for the drainpipe. The hollow rotary piston 4 is divided into chambers K, which are provided with drain holes L. It is apparent from FIG. 4 that the hollow rotary piston 4 has a perforated shell 4a, which is covered by a fine sheet metal screen 19 and a filter liner 18. The gate 16' carries at its tip a resilient element 20 provided with a scraping blade 21.

As a press for removing moisture, the apparatus operates as follows:

The material from which moisture is to be removed in a squeezing operation is sucked in through the suction opening or inlet pipe S and during a rotation of the rotary piston 4 enters the handling chamber F to F,. This chamber is defined by the curved inside peripheral surface of the housing 1 and the rotary piston 4 having a periphery a-b-a'-b'. The rotary piston is oval or elliptical in cross-section. The periphery of the piston 4 has a cylindrical portion a-b, which is in sealing contact with the curved inside peripheral surface of the housing. The gate 16 and the scraping blade 21 that is secured to the gate 16 are controlled by a positively acting mechanism 17 to conform to the periphery of the rotary piston and prevent a return flow of material toward theinlet and into the handling chamber F,. If the hinged valve 10 is operated to reduce the cross-section of an outlet discharge conduit 22, there will be a build-up of pressure in the handling chamber F. Thereby the liquid contained in the material will be forced through the screen and filter at the periphery of the drum and then will flow into the chambers K of the hollow rotary piston and from the latter through the hollow driving shaft 5 and the drainpipe 6, from which the liquid is pumped by the pump P through the conduits l4 and 15. The pressure applied can be adjusted by the spring 12 and the lever 11. The latter is firmly connected to the hinged valve 10. The residues of squeezed solid material adhering to the peripheral screen of the press piston are continuously removed by a scraping and shearing blade 21 secured to the gate 16. The resilient member 20 enables a movement of the shearing bladeso that the same can pass without difficulty over the irregularities in the peripheral screen of the rotary piston. The gate 16 is positively controlled so that its tip M follows the contour of the piston with a suitable clearance.

The means 17 for positively controlling the gate 16 are not described in detail herein because they have been disclosed in existing patents. One example is the mechanism disclosed in US. Pat. No. 2,484,403 to Dearsley which mechanism feeds the knives forwardly as they wear during operation of the rotary type machine. Another example is the mechanisms that are utilized with doctors 15, 16 and 17 of the rotary drum apparatus of US. Pat. No. 3,220,340 to Frykhult.

A vacuum is continuously maintained in the chambers K of the hollow rotary piston. For this purpose, almost the entire peripheral surface of the rotary piston is'available except for the cylindrical portion a-b. The liquid which has been sucked by the vacuum flows through openings L in the piston hub and the hollow driving shaft into a stationary drainpipe, which has an inlet opening T only at the top. Because the vacuum in the chambers K prevents a sucking of liquid into the drainpipe, the liquid can flow off only by gravity and each of the revolving chambers will be emptied when it is in its uppermost position. The chambers K communicate with each other through openings B so that a vacuum is constantly maintained in all chambers. The evacuation is effected through the drain pipe 6 and the conduit 13, which is connected toa vacuum pump VP. A liquid pump LP also contributes to the evacuation.

The apparatus according to the invention is simple and inexpensive and yet removes liquid at a.high rate because two operations are performed at the same time.

The invention is of considerable economic significance in numerous fields of application. Some examples are as afruit press, a press for removal of moisture from paper pulp to wherein an adjustable moisture content is provided without need for an evaporation step that consumes a large amount of time and energy; and a press for removal of moisture from sewage, sludge with recovery of fertilizer cake. The last-mentioned use is of special importance because the existing apparatus are not satisfactory and involve a very high capital requirement.

What is claimed is:

1. Apparatus for removing moisture from flowable material by the actions of pressure and vacuum, comprising a housing having sidewalls and end walls to define an enclosed area,

an inlet suction opening in the upper portion of the housing to receive the material,

a drum having a generally elliptical shaped cross-section and being rotatably mounted along its longitudinal axis within said housing, means to rotate said drum about its longitudinal axis, said drum being provided with a perforated filter surface through which substantial separation of the moisture takes place, said drum having cavity means therein through which the filtered material will flow from the perforated filter surface,

said drum being arranged eccentrically within said housing thereby providing a narrowing peripheral passageway between said drum and the interior sidewall of said housa handling chamber having a suction end at said narrowing passageway through which said filtered material passes,

a first outlet conduit means-communicating with said handling chamber to process the discharge of the filtered material therefrom, a second outlet conduit means communicating with said cavity means of said drum to process the discharge of the liquid therefrom,

and a vacuum and liquid pump means communicating with said second outlet conduit means to assist in discharging the liquid therefrom.

2. Apparatus as set forth in claim 1, in which said perforated filter surface comprises an outer screen and an inner filter liner.

3. Apparatus as set forth in claim 1, which includes partitioning means dividing said cavity means into a plurality of chambers which communicate with each other.

4. Apparatus as set forth in claim 3, in which each of said chambers is provided with a drain hole.

5. Apparatus as set forth in claim 4, in which said rotating means include a driving shaft having a hollow portion which communicates with said vacuum and liquid pump means and is formed with inlet openings adapted to register with each of said drain holes.

6. Apparatus as set forth in claim 5, in which said suction and liquid pump means are connected to said hollow portion of said shaft by a drainpipe, said drainpipe extends in said hollow portion and is held against rotation therewith and provided at its top with inlet openings adapted to register with each of said inlet openings of said hollow portion.

7. Apparatus as set forth in claim 1, which includes a scraping blade and resilient means arranged to maintain said blade in contact with said perforated filter surface on the outside thereof to clean the same.

8. Apparatus as set forth in claim I, which includes a backed gate mounted within said housing to selectively maintain a sealing contact with said perforated filter surface.

9. Apparatus as set forth in claim 1, which includes an adjustable throttle valve that controls the cross-section of said first outlet conduit means.

* I l k 0' 

1. Apparatus for removing moisture from flowable material by the actions of pressure and vacuum, comprising a housing having sidewalls and end walls to define an enclosed area, an inlet suction opening in the upper portion of the housing to receive the material, a drum having a generally elliptical shaped cross-section and being rotatably mounted along its longitudinal axis within said housing, means to rotate said drum about its longitudinal axis, said drum being provided with a perforated filter surface through which substantial separation of the moisture takes place, said drum having cavity means therein through which the filtered material will flow from the perforated filter surface, said drum being arranged eccentrically within said housing thereby providing a narrowing peripheral passageway between said drum and the interior sidewall of said housing, a handling chamber having a suction end at said narrowing passageway through which said filtered material passes, a first outlet conduit means communicating with said handling chamber to process the discharge of the filtered material therefrom, a second outlet conduit means communicating with said cavity means of said drum to process the discharge of the liquid therefrom, and a vacuum and liquid pump means communicating with said second outlet conduit means to assist in discharging the liquid therefrom.
 2. Apparatus as set forth in claim 1, in which said perforated filter surface comprises an outer screen and an inner filter liner.
 3. Apparatus as set forth in claim 1, which includes partitioning means dividing said cavity means into a plurality of chambers which communicate with each other.
 4. Apparatus as set forth in claim 3, in which each of said chambers is provided with a drain hole.
 5. Apparatus as set forth in claim 4, in which said rotating means include a driving shaft having a hollow portion which communicates with said vacuum and liquid pump means and is formed with inlet openings adapted to register with each of said drain holes.
 6. Apparatus as set forth in claim 5, in which said suction and liquid pump means are connected to said hollow portion of said shaft by a drainpipe, said drainpipe extends in said hollow portion and is held against rotation therewith and provided at its top with inlet openings adapted to register with each of said inlet openings of said hollow portion.
 7. Apparatus as set forth in claim 1, which includes a scraping blade and resilient means arranged to maintain said blade in contact with said perforated filter surface on the outside thereof to clean the same.
 8. Apparatus as set forth in claim 1, which includes a backed gate mounted within said housing to selectively maintain a sealing contact with said perforated filter surface.
 9. Apparatus as set forth in claim 1, which includes an adjustable throttle valve that controls the cross-section of said first outlet conduit means. 